Adaptive Planar Point Location

We present a self-adjusting point location structure for convex subdivisions. Let n be the number of vertices in a convex subdivision S. Our structure for S uses O(n) space and processes any online query sequence sigma in O(n + OPT) time, where OPT is the minimum time required by any linear decision tree for answering point location queries in S to process sigma. The O(n + OPT) time bound includes the preprocessing time. Our result is a two-dimensional analog of the static optimality property of splay trees. For connected subdivisions, we achieve a processing time of O(|sigma| log log n + n + OPT)

Dynamic Distribution-Sensitive Point Location

We propose a dynamic data structure for the distribution-sensitive point location problem. Suppose that there is a fixed query distribution in $\mathbb{R}^2$, and we are given an oracle that can return in $O(1)$ time the probability of a query point falling into a polygonal region of constant complexity. We can maintain a convex subdivision $\cal S$ with $n$ vertices such that each query is answered in $O(\mathrm{OPT})$ expected time, where OPT is the minimum expected time of the best linear decision tree for point location in $\cal S$. The space and construction time are $O(n\log^2 n)$. An update of $\cal S$ as a mixed sequence of $k$ edge insertions and deletions takes $O(k\log^5 n)$ amortized time. As a corollary, the randomized incremental construction of the Voronoi diagram of $n$ sites can be performed in $O(n\log^5 n)$ expected time so that, during the incremental construction, a nearest neighbor query at any time can be answered optimally with respect to the intermediate Voronoi diagram at that time.Comment: To appear in Proceedings of the International Symposium of Computational Geometry, 202

An examination of stock market performance in China using accounting information

This study aims to examine the usefulness of China accounting information in reflecting the stock returns in China stock markets and to recognize the significant factors that are possibly related to the stock returns in A shares and B shares respectively.Peoples’ Republic of China accounting standard (PRC accounting standard) is used for A shares whereas International Accounting Standard (IAS) is used for B shares. By comparing the two accounting standards, we found that the definition of some items and concepts of the financial statements are different. Consequently, the values of the financial ratios are varied. In order to recognize the significant factors in A shares and B shares, the means of factor analysis was adopted to sort out important factors from a large number of financial ratios. For A shares, profitability, interest efficiency, liquidity, asset efficiency and earning power are found to be significant factors. While for B shares, the significant factors are profitability, asset efficiency, liquidity, operating efficiency and earning on interest expense. After running the regression with A shares daily returns and B shares daily returns to their respective significant factors, profitability, asset efficiency and earning power are found to be significant at 5% level in A shares and only profitability is found to be significant at 1% level for B shares

Experience of COVID-19 vaccination among primary healthcare workers in Hong Kong : a qualitative study

Studies show that coronavirus disease 2019 (COVID-19) vaccine hesitancy exists among healthcare workers (HCWs). Past personal experiences of vaccination, such as the seasonal influenza vaccination, influence individuals’ intention to receive future vaccinations. This study aimed to explore the experience of COVID-19 vaccination among primary care HCWs in Hong Kong. A qualitative study using semi-structured interviews was conducted. Twenty-eight HCWs (ten doctors, ten nurses, and eight supporting staff) working in nine government-funded primary care clinics in Hong Kong who had completed at least one dose of COVID-19 vaccination were interviewed. Four themes were generated, namely, the cognitive and emotional battle of vaccine hesitancy, catalysts for vaccine acceptance, blasting vaccination myths, and being a positive influence. Providing timely, adequate, and transparent vaccine information and addressing the specific concerns of HCWs about the COVID-19 vaccine could enhance their vaccination uptake in future. Specific vaccine promotion strategies, such as the sharing of vaccination experiences targeted at different subgroups of HCWs, may improve vaccine acceptance through informational social influence

Hong Kong's Mandatory Provident Fund system : a study of the evolution of governance and policy tools

published_or_final_versionPolitics and Public AdministrationMasterMaster of Public Administratio

Bidirectional predictions between Internet addiction and probable depression among Chinese adolescents

Background and aims The aim of the study is to investigate (a) whether probable depression status assessed at baseline prospectively predicted new incidence of Internet addiction (IA) at the 12-month follow-up and (b) whether IA status assessed at baseline prospectively predicted new incidence of probable depression at follow-up. Methods We conducted a 12-month cohort study (n = 8,286) among Hong Kong secondary students, and derived two subsamples. The first subsample (n = 6,954) included students who were non-IA at baseline, using the Chen Internet Addiction Scale (≤63), and another included non-depressed cases at baseline (n = 3,589), using the Center for Epidemiological Studies Depression Scale ( Discussion and conclusions The high incidence of probable depression is a concern that warrants interventions, as depression has lasting harmful effects in adolescents. Baseline probable depression predicted IA at follow-up and vice versa, among those who were free from IA/probable depression at baseline. Healthcare workers, teachers, and parents need to be made aware of this bidirectional finding. Interventions, both IA and depression prevention, should thus take both problems into consideration

Ten-year population trends of immunoglobulin use, burden of adult antibody deficiency and feasibility of subcutaneous immunoglobulin (SCIg) replacement in Hong Kong Chinese

BackgroundAdult antibody deficiency remains under-recognised and under-studied – especially among Asian populations. Patterns of immunoglobulin use and the feasibility of subcutaneous immunoglobulin (SCIg) replacement among Chinese patients remains unclear.ObjectiveTo investigate the trends of immunoglobulin use, burden of adult antibody deficiency and the outcomes of patients on SCIg compared to intravenous immunoglobulin (IVIg) replacement in Hong Kong through a retrospective observational study.MethodsPopulation-wide data of immunoglobulin recipients in Hong Kong between 2012 and 2021, and longitudinal clinical data of adult immunodeficiency patients at Queen Mary Hospital were collected and analysed.ResultsTotal immunoglobulin consumption and recurrent immunoglobulin recipients increased continuously from 175,512g to 298,514g (ρ=0.99, p<0.001) and 886 to 1,508 (ρ=0.89, p=0.001) between 2012-21 in Hong Kong. Among 469 immunoglobulin recipients at Queen Mary Hospital in 2021, 344 (73.3%) were indicated for replacement. Compared to those on IVIg (n=14), patients on SCIg replacement (n=8) had fewer immunodeficiency-related hospitalisations (IRR=0.11) and shorter duration of hospitalisation stay (IRR=0.10) per year, as well as better quality of life (SF-36v2 Health Survey and Life Quality Index). Estimated annual healthcare cost of SCIg replacement per patient was lower than that of IVIg (HKD196,850 [USD25,096] vs HKD222,136 [USD28,319]).ConclusionThere was a significantly increasing burden of adult antibody deficiency and immunoglobulin consumption in Hong Kong. SCIg was feasible and more cost-effective when compared to IVIg, with SCIg patients experiencing better clinical outcomes and quality of life. Future prospective studies to confirm the long-term efficacy and superiority of SCIg are required